[tex]\begin{array}{ccll} \stackrel{fraction}{chapter}&hour\\ \cline{1-2} \frac{4}{5}&\frac{1}{4}\\[1em] x&3 \end{array}\implies \cfrac{~~\frac{4}{5} ~~}{x}=\cfrac{~~ \frac{1}{4}~~}{3}\implies \cfrac{~~\frac{4}{5} ~~}{\frac{x}{1}}=\cfrac{~~ \frac{1}{4}~~}{\frac{3}{1}}\implies \cfrac{4}{5x}=\cfrac{1}{12} \\\\\\ 48=5x\implies \cfrac{48}{5}=x\implies 9\frac{3}{5}=x[/tex]
